Tyler Moore drove in three runs and Ian Desmond went 4-for-5 with a pair runs scored as the Nats took the opener of a three-game series.
Jordan Zimmermann (3-0) notched a complete-game win, surrendering three runs on six hits and a walk.
Marlins starter Wade LeBlanc (0-3) was roughed up seven runs on nine hits and two walks over a 3 2/3-inning effort.
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